For my work I'm researching a good laptop that would be higher end
(cost not a huge factor, something that will have a long lifespan, in
years) laptop.. One with a docking station with support for dual
monitors.

This would have a DVD player/burner, the ability to expand to 4gb of
memory.. A large harddrive capable of holding lots of data.

This unit would be carried at conferences alot for hours on end.. so
it cant be too heavy. (Maybe a 17", but this may be pushing it?.. 15.4
Ideally i guess)

Any thoughts on types out there with docking stations?

Thanks